To provide an idle-speed controller in which the degree of freedom is improved in selecting characteristics of throttle valve opening, and the resolution for the opening change of the valve is improved.

An intake path 2 of a throttle body 1 is opened/closed by the throttle valve 4 placed in the throttle valve stem 3. A throttle valve lever 5 is provided to the end of the valve stem 3. A cam lever 10 is placed at one end of a rotatably supported link shaft 9 and a link lever 11 is placed at the other end. A slider 12 of a stepping motor M is connected to the link lever 11. A cam part 10A of the cam lever 10 is connected to a roller 8 of the valve lever 5. The linear motion of the slider 12 is transmitted through the link lever 11 to the link shaft 9 to cause a rotary displacement of the link shaft 9. Rotation of the cam lever 10 caused by rotation of the link shaft 9 is transmitted to the throttle-valve lever 5, and the valve 4 opens an idle opening in accordance with rotation of the stepping motor M.